Locke like Doc by Proserpina

First time posting here however the theory by “Sawyer’s optician”, “John Locke isn’t dead and the coming war” – had a couple of bits that triggered this. I commented on his theory as a jumping off point, however figured I should just post it proper!

Remember how on the island (S4)there was the washed ashore dead doctor from the freighter (a future doc depending on your perception), and yet on the freighter itself the doctor (present or past doc, depending on how you look at it) was still alive?

I believe that the dead Locke in the box is from the future and the walking around on the island Locke is from the present. So he isn't a fake Locke, he's a "present Locke". He could also be a "past" Locke (the walking around Locke) but regardless, box Locke is still from the future. And it’s likely that this walking around “present Locke” gets future flashes (a la Desmond) and also knows when he’s going to die (also a la Desmond, hello the book Desmond's going to read before he dies – how does he know when he’s going to die?)

So maybe "present John" has an island "3 year" best before date - meaning that his future self dies 3 years in the future (remember after he turned the FDW he went 3 years into the future or close to it, but only had 3 months on the island), so therefore island Locke (present or past, again depending on your perspective as the viewer) has 3 more years of life on the island before he dies in the future.....
I strongly think that the doctor body & time mismatch of living on the freighter (past) and dead on the beach (future) is our clue for the same situation existing for John Locke.

(Go easy on me!)